Particle production apparatus, particle production method and method for producing semiconductor encapsulating resin composition

ABSTRACT

Particle production apparatus  1  including processing section  3  in which a processing liquid is adhered to a surface of each of inorganic particles contained in a powder material, chamber  4  connected to processing section  3  at a downstream side thereof in which the powder material is separated from gas carrying the material, powder material supply device  50  with supply portion  5  and supply unit  6  for supplying the powder material into processing section  3 , and processing liquid spraying device  70  having a nozzle  7 , a pump  8 , a supply unit  9  for supplying the processing liquid, and a high-pressure gas (air) generating unit  11 . Processing liquid spraying device  70  is configured to spray processing liquid as droplets onto the powder material just after the powder material being supplied into the processing section  3 . Preferably, a volume of the processing section  3  is smaller than a volume of the chamber  4.

This application is a Divisional of, and claims priority to, applicationSer. No. 13/581,923, filed Aug. 30, 2012. application Ser. No.13/581,923 is the U.S. National Phase of PCT/JP2011/053914, filed Feb.23, 2011. Priority is also claimed to Japanese patent application No.2010-071116, filed in Japan on Mar. 25, 2010. All of these priorapplications are hereby expressly incorporated by reference into thepresent application.

The present invention relates to a particle production apparatus, aparticle production method and a method for producing a semiconductorencapsulating resin composition.

BACKGROUND OF THE INVENTION

There is known a semiconductor package in which a semiconductor chip(semiconductor element) is covered (encapsulated) with a resin-madeencapsulating (sealing) material. The encapsulating material for thesemiconductor chip is produced by molding a resin composition through,e.g., a transfer molding method.

A process for producing the resin composition from a powder materialthereof includes a surface treatment process in which a processingliquid such as a coupling agent is allowed to adhere to surfaces ofinorganic particles such as silica particles (filler material) containedin the powder material of the resin composition.

In this surface treatment process, the silica particles are injectedinto a chamber from an inlet port thereof, and the coupling agent isalso sprayed into the chamber from an opposite side with respect to theinlet port while the silica particles are spirally swirled in thechamber (for example, see patent document 1). In this configuration, apart of the coupling agent is contacted with the silica particles uponspraying the coupling agent and the remaining coupling agent is swirledand contacted with the other silica particles in the chamber duringswirling of the silica particles so that the coupling agent adheres tothe surfaces of the silica particles. As a result, a mixing property ofresin particles constituting the resin composition and the silicaparticles is enhanced, thereby easily mixing the silica particles andthe resin particles since the silica particles are coated with thecoupling agent.

However, according to the above method, in the surface treatmentprocess, there is a problem in that the silica particles are aggregated.In this case, it is difficult to uniformly mix the silica particles(inorganic particles) with the resin particles (resin composition).

Patent Document 1: JP-A 2003-275555.

It is an object of the present invention to provide a particleproduction apparatus, a particle production method and a method forproducing a semiconductor encapsulating resin composition, by which aprocessing liquid is allowed to adhere to inorganic particles containedin a powder material reliably while aggregation of the inorganicparticles is suppressed.

In order to achieve the object, one aspect of the present invention isdirected to a particle production apparatus which is configured so thata processing liquid adheres to a surface of each of inorganic particlescontained in a powder material, the particle production apparatuscomprising:

a processing section in which the processing liquid is allowed to adhereto the surface of each of the inorganic particles;

a chamber connected to the processing section at a downstream sidethereof in which the powder material is separated from gas carrying thepowder material;

a powder material supply device which supplies the powder material intothe processing section; and

a processing liquid spraying device which sprays the processing liquidas droplets to the powder material just after the powder material beingsupplied into the processing section,

wherein after the processing liquid sprayed to the powder materialadheres to the surface of each of the inorganic particles contained inthe powder material in the processing section, the powder material istransferred into the chamber so that the powder material is separatedfrom the gas.

In the particle production apparatus of the present invention, it ispreferred that the processing liquid spraying device comprises: anozzle; a gas supply device for supplying the gas having a pressurebeing equal to or higher than 0.3 MPa to the nozzle; and a processingliquid supply device for supplying the processing liquid into thenozzle, and

wherein the processing liquid is sprayed from the nozzle into theprocessing section due to the pressure of the gas.

In the particle production apparatus of the present invention, it ispreferred that the processing liquid supply device is a pump.

In the particle production apparatus of the present invention, it ispreferred that the droplets of the processing liquid sprayed from theprocessing liquid spraying device include small-sized droplets having aparticle size being equal to or less than 20 and the processing liquidspraying device is configured so that a ratio of the small-sizeddroplets to the total of the sprayed droplets becomes equal to or morethan 80 wt %.

In the particle production apparatus of the present invention, it ispreferred that the particle production apparatus is configured so that aswirl stream of the gas is generated in the chamber by spraying theprocessing liquid using the processing liquid spraying device.

In the particle production apparatus of the present invention, it ispreferred that the chamber has a cylindrical shape and the processingsection has a central axis and an outlet port connected to the chamber,

wherein the processing section is connected to a side portion of thechamber such that the central axis of the processing section is inclinedwith respect to a direction of a radius of the chamber which passesthrough the outlet port of the processing section, and

wherein the particle production apparatus is configured so that a swirlstream of the gas is generated in the chamber by spraying the processingliquid using the processing liquid spraying device.

In the particle production apparatus of the present invention, it ispreferred that the inorganic particles are constituted of silica and theprocessing liquid is a coupling agent.

In order to achieve the object, another aspect of the present inventionis directed to a particle production method by which a processing liquidis allowed to adhere to a surface of each of inorganic particlescontained in a powder material, wherein the powder material is suppliedinto a processing section, and the processing liquid is sprayed asdroplets to the powder material just after the powder material beingsupplied into the processing section, thereby allowing the processingliquid to adhere to the surface of each of the inorganic particlescontained in the powder material, and then the powder material istransferred into a chamber so that the powder material is separated fromgas carrying the powder material.

In the particle production method of the present invention, it ispreferred that the processing liquid and the gas having a pressure beingequal to or higher than 0.3 MPa are supplied into a nozzle so that theprocessing liquid is sprayed from the nozzle into the processingsection.

In the particle production method of the present invention, it ispreferred that an average particle size of the inorganic particles is inthe range of 0.5 to 100 μm.

In the particle production method of the present invention, it ispreferred that when the processing liquid is sprayed to the powdermaterial so that the processing liquid adheres to the surface of each ofthe inorganic particles contained in the powder material, there is acase that the powder material includes aggregated particles eachcomprised of the inorganic particle and the adhering processing liquidwherein each aggregated particle having a particle size of 150 μm ormore, but a ratio of such aggregated particles to the whole of thepowder material is equal to or less than 1 wt % of the powder material.

In order to achieve the object, the other aspect of the presentinvention is directed to a method for producing a semiconductorencapsulating resin composition comprising:

allowing the processing liquid to adhere to the surface of each of theinorganic particles contained in the powder material by the particleproduction method of the present invention; and

mixing a composition containing a powder material constituted of a resinand the powder material containing the inorganic particles to which theprocessing liquid adheres.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process chart showing a producing process of a resincomposition.

FIG. 2 is a cross section view (partial cross section view)schematically showing a particle production apparatus according to oneembodiment of the present invention.

FIG. 3 is a plain view schematically showing a chamber and a processingsection of the particle production apparatus shown in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinbelow, a particle production apparatus, a particle productionmethod and a method for producing a semiconductor encapsulating(sealing) resin composition according to the present invention will bedescribed in detail based on the preferred embodiments shown in theaccompanying drawings.

FIG. 1 is a process chart showing a producing process of a resincomposition. FIG. 2 is a cross section view (partial cross section view)schematically showing a particle production apparatus according to oneembodiment of the present invention. FIG. 3 is a plain viewschematically showing a chamber and a processing section of the particleproduction apparatus shown in FIG. 2.

In the following description, the upper side in FIG. 2 will be referredto as “upper”, the lower side will be referred to as “lower”, the leftside will be referred to as “left”, and the right side will be referredto as “right”.

A particle production apparatus 1 shown in FIG. 2 is an apparatus usedin a surface treatment process (inorganic particle production process)to produce a resin composition as a molded body (compact). Prior todescribing the particle production apparatus 1, description will befirst made on the overall producing process which begins with the supplyof raw materials and ends with the production of a resin composition forcovering (encapsulating) a semiconductor chip (semiconductor element).

At first, individual materials as raw materials of the resin compositionare prepared. The raw materials include a resin, a curing agent, afiller material (inorganic filler material, inorganic particles) and acoupling agent (processing liquid). If necessary, the raw materials mayfurther include a curing accelerator. It is preferable to use an epoxyresin as the resin.

Examples of the epoxy resin include a cresol novolac type epoxy resin, abiphenyl type epoxy resin, a dicyclopentadiene type epoxy resin, atriphenol methane type epoxy resin and a multi-ring aromatic type epoxyresin.

Examples of the curing agent include a phenol novolac type resin, aphenol aralkyl type resin, a triphenol methane type resin and amulti-ring aromatic resin.

Examples of the filler material (inorganic filler material, inorganicparticles) include silica such as a fused silica (having a crushed shapeor a spherical shape) or a crystalline silica and an alumina.

Examples of the coupling agent include a silane coupling agent (silanecompound) such as γ-glycidoxypropyltrimethoxysilane,γ-aminopropyltrimethoxysilane or γ-mercaptopropyltrimethoxysilane,vinyltriethoxysilane. Examples of the curing accelerator include aphosphor compound and an amine compound.

Specific one of the materials stated above may be excluded from the rawmaterials. Other materials than set forth above may be further includedin the raw materials. Examples of the other materials include a coloringagent, a releasing agent, a flame retardant and a stress-reducing agent.

Examples of the flame retardant include a brominated epoxy resin, anantimony oxide based flame retardant, non-halo and non-antimony basedflame retardant. Examples of the non-halo and non-antimony based flameretardant include organic phosphor, metal hydrate and anitrogen-containing resin.

(Fine Pulverization)

As shown in FIG. 1, specific materials among the raw materials are firstpulverized (finely pulverized) by a first pulverizing device to have aspecified particle size distribution. Examples of the raw materials tobe pulverized include the resin, the curing agent, the curingaccelerator and other materials than the filler material. A part of thefiller material may be added into the raw materials to be pulverized. Asa result, a first composition including plural kinds of the pulverizedmaterials such as the resin, the curing agent and the curing acceleratoris obtained. As the first pulverizing device, it is possible to use acontinuous rotary ball mill and so forth.

(Surface Treatment (Particle Production))

A specified material among the raw materials, that is, all or a part(remaining part) of the filler material (inorganic particles), issubjected to a surface treatment by the particle production apparatus 1.Namely, in the surface treatment, a processing liquid such as thecoupling agent adheres to a surface of each of the inorganic particles.As a result, a second composition including a powder material containingthe inorganic particles is obtained. As the coupling agent adheres tothe surface of the filler material, a mixing property of the resin andthe curing agent with the filler material is enhanced, thereby easilymixing the filler material with the resin.

The powder material of the filler material may be constituted of onlythe filler material. Other materials than the filler material may befurther included in the powder material of the filler material. Further,the fine pulverization and the surface treatment may be performed eithersimultaneously or one after the other. The particle production apparatus1 will be described later.

(Mixing)

Next, the first composition obtained in the fine pulverization processand the second composition obtained in the surface treatment process,namely, the resin composition including plural kinds of powder materialsis mixed thoroughly by a mixing device. Each of the powder materials hasa different specific gravity. As the mixing device, it is possible touse a high-speed mixing device having rotary blades or the like.

(Kneading)

Next, the resin composition is kneaded by a kneading device. As thekneading device, it is possible to use, a kneading extruder such as asingle-axis type kneading extruder or a double-axis type kneadingextruder, or a roll type kneader such as a mixing roll and so forth.

(Degassing)

Next, the resin composition thus kneaded is degassed by a degassingdevice.

(Sheet Making)

Next, the massive resin composition thus degassed is molded into a sheetshape by a sheet-making device. As a result, a sheet shaped resincomposition (sheet shaped resin material) is obtained. As thesheet-making device, it is possible to use, e.g., a sheet-making roll.

(Cooling)

Next, the sheet shaped resin composition is cooled by a cooling device.This makes it possible to easily and reliably perform pulverization ofthe sheet shaped resin composition.

(Pulverization)

Next, the sheet shaped resin composition is pulverized by a secondpulverizing device to have a specified particle size distribution. As aresult, a pulverized composition is obtained. As the second pulverizingdevice, it is possible to use, e.g., a hammer mill, a knife mill or apin mill.

In this regard, the granular or powdery resin composition may beobtained not by way of the sheet-making, cooling and pulverizing steps.Instead, the granular or powdery resin composition may be obtained by,e.g., a hot cutting method in which a die having a small diameter isinstalled in an outlet port (discharge passage) of the kneading deviceand a molten resin composition discharged from the die is cut by acutter into granular resin composition having a specified length. Afterobtaining the granular resin composition by the hot cutting method, itis preferable to perform degassing while the temperature of the resincomposition remains high.

(Tablet Making)

Next, the powder compositions are compression-molded by a compactmanufacturing device (tablet-making device) to obtain resin compositionin the form of compacts.

The resin composition are used in, e.g., covering (encapsulating) asemiconductor chip (semiconductor element). In other words, the resincomposition is molded by, e.g., a transfer molding method. Asemiconductor chip is covered with the molded resin composition as anencapsulating material, thus manufacturing a semiconductor package.

The tablet-making process may be omitted and the powdery resincomposition may be used as final products. In this case, theencapsulating material can be formed by, e.g., a compression-moldingmethod or an injection-molding method.

Next, description will be given to the particle production apparatus 1.As shown in FIGS. 2 and 3, the particle production apparatus 1 is anapparatus which is configured so that the processing liquid adheres tothe surface of each of the inorganic particles contained in the powdermaterial. The particle production apparatus 1 includes a processingsection 3 in which the processing liquid is allowed to adhere to thesurface of each of the inorganic particles, a chamber 4 connected to theprocessing section 3 at a downstream side thereof in which the powdermaterial is separated from gas (air) carrying the powder material, apowder material supply device (inorganic particle supply device) 50having a supply portion 5 and a supply unit 6 for supplying the powdermaterial and the like into the processing section 3, and a processingliquid spraying device 70 having a nozzle 7, a pump 8, a supply unit 9for supplying the processing liquid, a high-pressure gas (air)generating unit 11 and the like. The processing liquid spraying device70 is configured to spray the processing liquid as droplets (in dropletstate) onto the powder material just after the powder material beingsupplied into the processing section 3.

The chamber 4 has a side portion formed into a cylindrical (tubular)shape. A lower end portion of the chamber 4 is formed into a taperingshape having an inner diameter gradually decreasing from an upper sidetoward a lower side thereof. A lower opening of the chamber 4constitutes (serves as) a discharge passage of the powder materialhaving been processed (to which the processing liquid adheres).

A filter 41 which permits passage of the gas (air) but does not permitpassage of the powder material and the processing liquid (liquid) isprovided at an upper portion of the chamber 4. The filter 41 serves asan air vent portion for discharging therethrough the gas (air) existingwithin the chamber 4. Further, the filter 41 is arranged so as to closean upper opening of the chamber 4.

The receiving unit not shown in the drawings for receiving the powdermaterial which has been processed in the chamber 4 and then dischargingit from the chamber 4 is provided at the lower side of the chamber 4.

The processing section 3 has a cylindrical (tubular) shape whose one endside (upstream side) is closed. The processing section 3 is provided atan upper side of the side portion (lateral surface) of the chamber 4. Anoutlet port 31 of the processing section 3 is an aperture connected toan inside of the chamber 4. Further, the processing section 3 providedat the side portion of the chamber 4 is in a state that an axis line(central axis) 32 of the processing section 3 is inclined with respectto a direction of a radius of the chamber 4 that passes through theoutlet port 31 (center of the outlet port 31) in a planar view. Due tothis configuration of the processing section 3, when the processingliquid is sprayed by the processing liquid spraying device 70, it ispossible to generate a swirl stream of the gas (air) in the chamber 4.

Each of dimensions of the processing section 3 and the chamber is notparticularly limited to a specific value, but it is preferred that avolume of the processing section 3 is smaller than a volume of thechamber 4.

Specifically, the dimension of the processing section 3 is notparticularly limited to a specific value if the processed powdermaterial obtained by coupling the processing liquid injected (sprayed)from the nozzle 7 into the processing section 3 with the powder materialsupplied from an outlet port 52 of the supply portion 5 (describedlater) into the processing section 3 is discharged to the chamber 4without adhering to a wall surface of the processing section 3. However,in this case, a radius of the processing section 3 (length in a verticaldirection of the processing section shown in FIG. 2) is preferably inthe range of 20 to 100 mm, and more preferably in the range of 30 to 80mm. Simultaneously, a length of the processing section 3 (shortestlength between a connecting portion of the processing section 3 with thechamber 4 and an installation surface of the nozzle 7 to the processingsection 3) is preferably in the range of 50 to 250 mm, and morepreferably in the range of 100 to 200 mm. If the radius of theprocessing section 3 is less than the lower limit value noted above orthe length of the processing section 3 exceeds the upper limit valuenoted above, there is a possibility that the processing powder materialadheres to the wall surface of the processing section 3. As a result,aggregation of the powder particles is generated or the processing ofthe powder particles is impeded. On the other hand, if the radius of theprocessing section 3 exceeds the upper limit value noted above or thelength of the processing section 3 is less than the lower limit valuenoted above, there is a possibility that the swirl stream of the gas(air) generated in the chamber 4 flows into the processing section 3. Asa result, the processing of the powder particles becomes unstable.

Further, the dimension of the chamber 4 is not particularly limited to aspecific value if the swirl stream of the gas (air) can be generated inthe chamber 4 and the powder material can be separated from the gas(air) in the chamber 4, but a radius of the chamber 4 is preferablyequal to or more than 100 mm, and more preferably in the range of 200 to300 mm. Simultaneously, a height of the chamber 4 is preferably equal toor more than 900 mm, and more preferably in the range of 1.5 to 3.0 m.If the radius and the height of the chamber 4 are less than the lowerlimit value noted above, there is a possibility that the swirl stream ofthe gas (air) generated in the chamber 4 is not sufficiently generated.As a result, clogging of the filter is generated. If the radius and theheight of the chamber 4 are less than the preferable upper limit value,it is possible to decrease an area to which the powder material adheresin the chamber 4. As a result, an advantage of yield of the powdermaterial becomes high.

The supply portion 5 is provided at an upper portion of the processingsection 3. The supply portion 5 is connected to the processing section 3and the powder material is supplied into the processing section 3. Anupper end portion of the supply portion 5 is formed into a taperingshape having an inner diameter gradually increasing from a lower sidetoward an upper side thereof. An upper opening of the supply portion 5serves as a supply port for the powder material and a lower opening ofthe supply portion 5 serves as the outlet port for the powder material.

The supply unit 6 for supplying the powder material into the supplyportion 5 is provided at an upper side of the supply portion 5. Thesupply unit 6 is configured to adjust a flow rate of the powder materialsupplied into the supply portion 5.

A major portion of the powder material supply device 50 is constitutedof the supply portion 5 and the supply unit 6.

Further, the nozzle 7 is installed in a right (upstream side) endportion of the processing section 3. The nozzle 7 is connected to theprocessing section 3 and sprays the processing liquid into theprocessing section 3. The nozzle 7 is arranged such that an axis line(central axis) 71 of the nozzle 7 is parallel to the axis line 32 of theprocessing section 3 (In the configuration shown in the drawings, theaxis line 71 and the axis line 32 are arranged so as to correspond witheach other).

Further, the axis line 71 of the nozzle 7 and an axis line (centralaxis) 51 of the supply portion 5 are intersected with each other (In theconfiguration shown in the drawings, the axis line 71 is perpendicularto the axis line 51). Namely, a spraying direction of the processingliquid from the nozzle 7 into the processing section 3 (a direction of acentral line of the spraying direction in which the processing liquid isradially sprayed) and an injecting (introducing) direction of the powdermaterial are intersected with each other.

Further, a gap is formed between a distal end portion of the nozzle 7and the outlet port 52 of the supply portion 5. A distance of the gap Lis not particularly limited to a specific value and is appropriately setdepending on conditions, but is preferably in the range of about 0 to 50mm, and more preferably in the range of about 5 to 20 mm.

If the distance of the gap L exceeds the upper limit value noted above,depending on the other conditions, there is a possibility that theprocessing liquid sprayed from the nozzle 7 adheres to the wall surfaceof the processing section 3 so that the appropriate processing of thepowder material cannot be performed. Further, there is a possibilitythat the gas (air) including the processing liquid sprayed from thenozzle 7 is leaked from the supply portion 5, thereby interfering thesupplying of the powder material from the powder material supply device50. On the other hand, if the distance of the gap L is less than thelower limit value noted above (such a case that a value of the distanceof the gap L is minus (the distal end portion of the nozzle 7 isprotruded) is included), depending on the other conditions, there is apossibility that the powder material adheres to the distal end of thenozzle 7 so that the processing liquid cannot be stably supplied fromthe nozzle 7. Further, this causes generation of aggregation of thepowder particles.

The high-pressure gas (air) generating unit 11 is connected to thenozzle 7 through a conduit line 121. The high-pressure gas generatingunit 11 is a device for compressing gas (air) to feed a high-pressuregas (compressed gas) and is configured to adjust a flow rate and apressure of the high-pressure gas. In this regard, one end portion ofthe conduit line 121 is connected to an upper portion of the nozzle 7.

Further, the supply unit 9 is connected to the nozzle 7 through aconduit line 122. The supply unit 9 is configured to adjust a flow rateof the processing liquid being supplied into the nozzle 7. The supplyunit 9 can stably supply the processing liquid in cooperation with thepump 8 described later. In this regard, one end portion of the conduitline 121 is connected to a right (upstream side) end portion of thenozzle 7.

Further, the pump 8 for feeding the processing liquid (liquid) isprovided at the middle of the conduit line 122 (between the nozzle 7 andthe supply unit 9). By providing the pump 8 at the middle of the conduitline 122, the flow rate of the processing liquid can be reliably set totarget values without being influenced by the gas fed by thehigh-pressure gas generating unit 11.

A major portion of the processing liquid spraying device 70 isconstituted of the nozzle 7, the pump 8, the supply unit 9, thehigh-pressure gas generating unit 11 and the conduit lines 121 and 122.

Further, a major portion of a processing liquid supply device isconstituted of the pump 8, the supply unit 9 and the conduit line 122.

Further, a major portion of a gas supply device is constituted of thehigh-pressure gas (air) generating unit 11 and the conduit line 121.

Next, description will be made on the surface treatment process(inorganic particle production process) and the operation of theparticle production apparatus 1 in the surface treatment process.Hereinbelow, the description will be representatively made on a casethat all of the powder material being subjected to the surface treatmentprocess is constituted of the inorganic particles, but it is needless tosay that the powder material may contain the other components than theinorganic particles.

(Surface Treatment Process)

In the surface treatment process, the processing liquid such as thecoupling agent adheres to the surface of each of the all or a part ofthe inorganic particles as the filler material by the particleproduction apparatus 1, thereby manufacturing the inorganic particles towhich the processing liquid adheres. This makes it possible to obtainthe powder material containing the inorganic particles to which theprocessing liquid adheres (the second composition). As the processingliquid (coupling agent) adheres to the surface of the inorganicparticles, that is, the inorganic particles are coated with the couplingagent, a mixing property of the resin and the curing agent with theinorganic particles is enhanced, thereby easily mixing the fillermaterial with the resin.

In the surface treatment process, the inorganic particles (powdermaterial) are received in the supply unit 6 and the processing liquid isstored in the supply unit 9.

An average particle size of the inorganic particles is not particularlylimited to a specific value, but is preferably in the range of about 0.5to 100 μm, and more preferably in the range of about 1 to 50 μm. Thismakes it possible to easily and uniformly mix the inorganic particleswith the resin composition in the next (later) mixing process.

Next, the supply unit 6, the pump 8, the supply unit 9 and thehigh-pressure gas (air) generating unit 11 are driven, respectively.

By doing so, the high-pressure gas compressed (compressed gas) is fedfrom the high-pressure gas generating unit 11 and injected from thenozzle 7 into the processing section 3, and then the high-pressure aircompressed is injected from the processing section 3 into the chamber 4.As a result, the swirl stream of the gas (gas and droplets of theprocessing liquid) is generated in the chamber 4. On the other hand, theprocessing liquid is supplied at a specific flow rate from the supplyunit 9 and transferred into the nozzle 7 by the pump 8. As a result, theprocessing liquid is formed into fine droplets and injected from thenozzle 7 with the gas. Namely, the processing liquid is sprayed as fineparticles from the nozzle 7 into the processing section 3.

A pressure of the gas supplied into the nozzle 7 is not particularlylimited to a specific value and is appropriately set depending onconditions, but is preferably equal to or higher than 0.3 MPa, and morepreferably in the range of 0.4 to 0.6 MPa.

If the pressure of the gas supplied into the nozzle 7 is less than thelower limit value noted above, depending on the other conditions, aparticle size of each of the droplets of the processing liquid sprayedfrom the nozzle 7 become large so that it is difficult to form thepreferable fine droplets of the processing liquid described later.Further, in this case, since dispersion property of the powder materialsupplied into the processing section 3 is low, it is difficult touniformly process the powder material.

In this regard, the pressure of the gas supplied into the nozzle 7 canbe adjusted by e.g., the high-pressure gas generating unit 11.

A particle size of each of the droplets of the processing liquid sprayedfrom the nozzle 7 is not particularly limited to a specific value and isappropriately set depending on conditions, but a ratio of the droplets(small-sized droplets) having a particle size being equal to or lessthan 20 μm to the total of the sprayed droplets is preferably equal toor more than 80 wt %, and more preferably in the range of 90 to 100 wt%.

If the ratio is less than the lower limit value noted above, dependingon the other conditions, the inorganic particles are aggregated tothereby readily generate an aggregation of the inorganic particles whenthe processing liquid is sprayed onto the inorganic particles.

An average particle size of each of the droplets of the processingliquid sprayed from the nozzle 7 is not particularly limited to aspecific value, but is preferably equal to or less than 20 μm, and morepreferably in the range of 0.5 to 15 μm.

This makes it possible to suppress the aggregation of the inorganicparticles when the processing liquid is sprayed onto the inorganicparticles.

Further, when the average particle size of the droplets of theprocessing liquid sprayed from the nozzle 7 is “a” and the averageparticle size of the inorganic particles is “b”, a/b is preferably equalto or less than 10, and more preferably in the range of about 0.02 to 1.

This makes it possible to suppress the aggregation of the inorganicparticles when the processing liquid is sprayed onto the inorganicparticles.

In this regard, a particle size distribution of the droplets of theprocessing liquid sprayed from the nozzle 7 can be measured by using alaser diffraction type spray particle size distribution measuringinstrument. The ratio of the droplets having a particle size being equalto or less than 20 μm and the average particle size of the droplets canbe calculated from a cumulative particle size distribution measured bythe measuring instrument noted above.

The inorganic particles are supplied at a specific flow rate from thesupply unit 6 and then supplied form the supply portion 5 into theprocessing section 3. The inorganic particles are fallen (transferred toa lower side of the supply portion 5), thereby being supplied into theprocessing section 3 by its own weight.

Just after the inorganic particles are supplied into the processingsection 3, the processing liquid is sprayed to the inorganic particlesfrom the nozzle 7, thereby allowing the processing liquid to adhere tothe surface of each of inorganic particles. Thereafter, the inorganicparticles thus processed are transferred and injected into the chamber 4together with the gas and the processing liquid injected (sprayed) fromthe nozzle 7. And then, the inorganic particles are transferred to alower side of the chamber 4 together with the gas and the processingliquid while the inorganic particles are swirled in the chamber 4. As aresult, the inorganic particles coated with the processing liquid aredischarged from the chamber 4 and then received in the receiving unit.

Further, an excess gas injected into the chamber 4 is separated from theinorganic particles and discharged to an outside of the chamber from thefilter 41. This makes it possible to maintain the pressure in thechamber 4 at a specific value. As a result, the inorganic particlesprocessed in the processing section 3 can be easily and reliablyintroduced into the chamber 4, thereby being received in the receivingunit.

In the inorganic particles thus processed, the aggregation of theinorganic particles (aggregated inorganic particles) is not generated,or even if the aggregation of the inorganic particles is generated, aparticle size of the aggregated inorganic particles is small or anamount of the aggregated inorganic particles is small.

Specifically, a ratio of the aggregated inorganic particles having asize being equal to or more than 150 μm to the whole of the inorganicparticles after being processed can be equal to or less than 1 wt %,especially equal to or less than 0.5 wt %.

This makes it possible to easily and reliably mix each of the powdermaterials with the resin composition uniformly in the mixing process.

As set forth above, according to the particle production apparatus 1,the processing liquid is sprayed to the powder material, therebyallowing the processing liquid to adhere to the surface of each of theinorganic particles contained in the powder material before the powdermaterial is transferred into the chamber 4. This makes it possible toeasily and reliably allow the processing liquid to adhere to the surfaceof each of the inorganic particles while the aggregation of theinorganic particles (powder material) is suppressed. As a result, in themixing process, the inorganic particles can be easily and uniformlymixed with the resin composition.

Further, since the particle production apparatus 1 has a system in whichthe processing liquid adheres to the surface of each of the inorganicparticles by spraying the processing liquid, it is possible to prevent(or suppress) metallic foreign substances from being mixed into thepowder material having been processed in the surface treatment process(in manufacturing the inorganic particles). As a result, when asemiconductor chip is encapsulated by the resin composition thusproduced, it is possible to prevent short circuit.

Furthermore, each of parts which makes contact with the powder materialin the particle production apparatus 1 of the present invention ispreferably constituted of a nonmetallic material. Examples of thenonmetallic material include a ceramics and a resin. This makes itpossible to prevent (or suppress) metallic foreign substances from beingmixed into the powder material having been processed in the surfacetreatment process (in manufacturing the inorganic particles). As aresult, when the semiconductor chip is encapsulated by the resincomposition thus produced, it is possible to prevent short circuit.

While the descriptions are given to the particle production apparatus,the particle production method and the method for producingsemiconductor encapsulating resin composition according to the presentinvention shown in the drawings, the present invention is not limitedthereto. Each component constituting the particle production apparatusmay be substituted for an arbitrary component having the same functionas it. Further, arbitrary structures also may be added thereto.

EXAMPLES

Next, description will be given to specific examples of the presentinvention.

<Raw Materials>

Raw materials used include following materials.

Fused silica (fused silica particles, having an average particle size of33 μm) is used as the inorganic particles.

γ-glycidoxypropyltrimethoxysilane (having a viscosity of 3.3 cSt at 25°C.) is used as the processing liquid (coupling agent) in Examples 1 and2 and Comparative Example 1. N-phenyl-γ-aminopropyltrimethoxysilane(having a viscosity of 8.0 cSt at 25° C.) is used as the processingliquid in Example 3.

Example 1

The coupling agent adhered to the surface of the fused silica using theparticle production apparatus 1 shown in FIG. 2 under the followingcondition:

the pressure of the air supplied into the nozzle being 0.5 MPa.

In this regard, a particle size distribution of droplets of the couplingagent sprayed from the nozzle having a ratio of the droplets having aparticle size being equal to or less than 20 μm (small-sized droplets)to the total of the sprayed droplets was 98 wt %, wherein the averageparticle size of the droplets was 8 μm.

Example 2

The coupling agent adhered to the surface of the fused silica in thesame manner as Example 1, except that the condition was changed to:

the pressure of the air supplied into the nozzle being 0.3 MPa.

In this regard, a particle size distribution of droplets of the couplingagent sprayed from the nozzle having a ratio of the droplets having aparticle size being equal to or less than 20 μm to the total of thesprayed droplets was 96 wt %, wherein the average particle size of thedroplets was 12 μm.

Example 3

The coupling agent adhered to the surface of the fused silica in thesame manner as Example 1, except that the kind of the processing liquid(coupling agent) was changed as noted above.

In this regard, a particle size distribution of droplets of the couplingagent sprayed from the nozzle having a ratio of the droplets having aparticle size being equal to or less than 20 μm to the total of dropletswas 85 wt %, wherein the average particle size of the droplets was 18μm.

Comparative Example 1

By using an apparatus shown in FIG. 4(c) of JP-A 2003-275555 (the patentdocument 1), the fused silica was injected into a chamber, and thecoupling agent was sprayed into the chamber from an opposite side withrespect to an inlet port from which the fused silica was injected whilethe fused silica was spirally swirled in the chamber. Thus, the couplingagent adhered to the surface of the fused silica under the followingconditions:

the pressure of the air used in injecting the fused silica into thechamber being 0.5 MPa; and

the pressure of the air used in spraying the coupling agent into thechamber being 0.5 MPa.

In this regard, a particle size distribution of droplets of the couplingagent sprayed into the chamber having a ratio of the droplets having aparticle size being equal to or less than 20 μm to the total of thesprayed droplets was 98 wt %, wherein the average particle size of thedroplets was 8 μm.

In Examples 1 to 3 and Comparative Example 1, the particle sizedistribution of the droplets of the coupling agent sprayed was measuredby using a laser diffraction type spray particle size distributionmeasuring instrument (manufactured by NIKKISO CO., LTD). The ratio ofthe droplets having a particle size being equal to or less than 20 μm tothe total of the sprayed droplets was calculated from a cumulativeparticle size distribution measured by this measuring instrument.

[Evaluation]

With regard to Examples 1 to 3 and Comparative Example 1, a ratio of theaggregated fused silica (fused silica particles) having a size beingequal to or more than 150 μm to the whole of the total fused silicaafter being processed was evaluated by using a measuring instrument(Powder Tester manufactured by Hosokawa Micron Corporation) under thefollowing conditions: an amplitude of 1 mm; the number of frequency of3,000 VPM; a measuring time of 60 seconds; a sieve having apertures of150 μm; and a sample weight of 6 g per time.

Example 1: 0.1 wt %

Example 2: 0.5 wt %

Example 3: 0.6 wt %

Comparative Example 1: 1.1 wt %

As it is apparent from the above evaluation, in Examples 1 to 3, a smallamount of the aggregated fused silica was generated, and satisfactoryresult was obtained.

In contrast, in Comparative Example 1, since a supply position of thefused silica is spaced apart from a supply position of the couplingagent, there is a low probability of collision between the fused silicaand the coupling agent. For the reason, the surface treatment to thefused silica was unevenly. Further, the fused silica swirled in thechamber adhered to a nozzle for supplying the coupling agent to therebygenerate an aggregation substance of the silica at the nozzle. As aresult, a large amount of the aggregated fused silica was generated.

INDUSTRIAL APPLICABILITY

With the present invention, it is possible to easily and reliably allowthe processing liquid to adhere to the surface of each of the inorganicparticles while the aggregation of the inorganic particles (powdermaterial) is suppressed. As a result, in the mixing process for mixingthe resin composition, the inorganic particles can be easily anduniformly mixed with the resin composition. For the reasons statedabove, the present invention is industrially applicable.

What is claimed is:
 1. A particle production method by which aprocessing liquid is allowed to adhere to a surface of each of inorganicparticles contained in a powder material, which particle productionmethod uses a particle production apparatus, wherein the particleproduction apparatus comprises: a chamber including a side portionhaving a cylindrical shape, wherein in the chamber the powder materialis separated from gas carrying the powder material; a processing sectionincluding a tubular portion with two ends, an outlet port provided atone of the ends and a wall portion provided at the other end and havinga through-hole, the tubular portion of the processing section directlyconnected to the side portion of the chamber through the outlet port ofthe processing section so as to protrude from the chamber, wherein inthe processing section the processing liquid is allowed to adhere to thesurface of each of the inorganic particles; a processing liquid sprayingdevice including a nozzle having a distal end, the nozzle connected tothe wall portion of the processing section via the through-hole of thewall portion; and a powder material supply device including a supplyportion having an outlet port, said outlet port having an edge closestto the nozzle, the supply portion connected to the tubular portion ofthe processing section through the outlet port of the supply portionsuch that a gap is formed along a longitudinal direction of the nozzlebetween the distal end of the nozzle and the edge of the outlet port ofthe supply portion closest to the nozzle, wherein the particleproduction method comprises: supplying the powder material into theprocessing section; spraying the processing liquid as droplets to thepowder material just after the powder material is supplied into theprocessing section; allowing the processing liquid to adhere to thesurface of each of the inorganic particles contained in the powdermaterial; and transferring the powder material into the chamber so thatthe powder material is separated from the gas carrying the powdermaterial.
 2. The particle production method as claimed in claim 1,wherein the processing liquid and a gas having a pressure being equal toor higher than 0.3 MPa are supplied to the nozzle so that the processingliquid is sprayed from the nozzle into the processing section.
 3. Theparticle production method as claimed in claim 1, wherein an averageparticle size of the inorganic particles is in the range of 0.5 to 100μm.
 4. The particle production method as claimed in claim 1, whereinwhen the processing liquid is sprayed to the powder material so that theprocessing liquid adheres to the surface of each of the inorganicparticles contained in the powder material, there is a case that thepowder material includes aggregated particles each comprised of theinorganic particle and the adhering processing liquid wherein eachaggregated particle having a particle size of 150 μm or more, but aratio of such aggregated particles to the whole of the powder materialis equal to or less than 1 wt % of the powder material.
 5. The particleproduction method as claimed in claim 1, wherein a ratio of the dropletshaving a particle size being equal to or less than 20 μm to the total ofthe sprayed droplets is in the range of 80 to 100 wt %.
 6. The particleproduction method as claimed in claim 5, wherein an average particlesize of the droplets of the processing liquid sprayed from the nozzle isin the range of 0.5 to 20 μm.
 7. The particle production method asclaimed in claim 6, wherein when the average particle size of thedroplets of the processing liquid sprayed from the nozzle is “a” and theaverage particle size of the inorganic particles is “b”, a/b is in therange of about 0.02 to
 1. 8. The particle production method as claimedin claim 1, wherein the inorganic particles are constituted of silicaand the processing liquid is a coupling agent.
 9. The particleproduction method as claimed in claim 1, wherein a radius of theprocessing section is in the range of 20 to 100 mm and a length thereofis in the range of 50 to 250 mm.
 10. The particle production method asclaimed in claim 1, wherein a distance of the gap is in the range of 5to 20 mm.
 11. The particle production method as claimed in claim 1,wherein the chamber is provided in a vertical direction and theprocessing section protrudes from the chamber in a horizontal direction.